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My 2003 CMC Dyno


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Thanks Neil!


The setup is basically:


94Z28 - stock bottom end with 98K mi on it

The heads are the stock castings that have been ported, the flow #'s are at the bottom. They have 2.00 / 1.56 valves, double springs and all the usual titanium hardware. The compression ratio is roughly 11.2 or so (maybe a tad higher)

1.6 roller rockers.

Cam is a 230/236 .565/.565 112LSA

Mac shorty headers into a y-pipe into a 3" catback into a fullsize muffler.

The fuel system uses the stock lines with a Walbro intank pump and Bosch 30# injectors.


I'm using the stock PCM but tuning was done using LT1Edit by Jason Swindle and me (More Jason than me at this point). It runs on 91 octane pump gas with no detonation problems at all. A couple of degrees of timing were pulled out accross the board to compensante for the higher compression ratio but after looking at the complete lack fo knock retard we saw on the dyno I think we'll try adding a bit more back in next time around and see if we can squeeze a bit more out. It got a bit lean at the top end, I've since switched to another program that's added a bit of fuel up high but we didn't run that one on the dyno (we ran out of time).


Its a very docile car to drive on the street. Right now this car is my daily driver / grocery getter and it does great in every day stop and go driving. Its an absolute blast to drive on the street, my major complaint with it is that traction is non existant in 1st and 2nd gear if you really get on it.



- Nick

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Very, very impressive; in fact unprecedented! Kudos to Nick.


The LS1 is able to do it pretty readily but I this is the first LT1 I have seen in that range with a smoggable cam and good street manners. Have you put it on a wideband at idle or on a smog machine at idle, Nick?



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Perry -

I havne't put it on a wideband at idle yet. I'll letcha know how it smogs in October. It should pass tho.


Neil -


The heads were done by a shop in South Carolina that builds Trans Am motors, I have the guy's email around here.


53cc chambers - 4.030 bore, 28"

Intake Exh

0.100 73.8 60.9

0.150 109.5 95.1

0.200 145.3 129.2

0.250 180.0 152.0

0.300 201.6 164.3

0.350 219.4 176.2

0.400 238.9 185.2

0.450 253.3 191.3

0.500 264.1 196.2

0.550 273.7 199.2

0.600 279.9 203.9

0.650 279.8 204.8


- Nick

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